System and method for establishing virtual boundaries for robotic devices

ABSTRACT

A method for detecting an alignment of a robot with a virtual line, including: transmitting a first signal with at least one first transmitter; receiving the first signal with a first receiver and a second receiver, wherein the first receiver and the second receiver are housed within a first passage and a second passage, respectively; detecting, with a controller coupled to the first receiver and the second receiver, the robot is aligned with the virtual line when the first receiver and the second receiver simultaneously receive the first signal, the virtual line being in line with and located at a midpoint between the first passage and the second passage; and actuating the robot to execute a particular movement type when the robot is aligned with the virtual line.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. Non-Provisional patentapplication Ser. No. 16/719,254, filed Dec. 18, 2019, which is aContinuation of U.S. Non-Provisional patent application Ser. No.14/850,219, filed Sep. 10, 2015, which claims the benefit of U.S.Provisional Patent Application Nos. 62/141,799, filed Apr. 1, 2015, and62/167,217, filed May 27, 2015, each of which is hereby incorporated byreference.

FIELD OF THE DISCLOSURE

This disclosure relates to robotic systems generally, and moreparticularly to providing virtual boundaries for limiting surfacecoverage by robotic devices. This invention relates to confining thesurface movement to defined areas of mobile robotic devices.

BACKGROUND

Robotic devices may operate within a confined portion of a physical areaor workspace. Mobile robots may perform routine tasks, such asvacuuming, sweeping, mopping, cutting grass, etc., without moving intocertain areas specified by the user. However, on occasion, a vacuumingrobot operating within a first area may be permitted to travel into asecond area prior to satisfactory completion of, for example, avacuuming task within the first area. In other instances, the vacuumingrobot may collide with and, potentially, damage a fragile or unstableobject that is not detected by sensors accessed by the vacuuming robot.In other instances, a user may simply prefer that a vacuuming robotremain outside of an area, for example, if the area is currently in use.Thus, it may be useful to confine a robotic device so as to operatewithin certain areas and to prevent unwanted transition between areas.

One approach toward confining robotic device may be to utilize physicalbarriers that block the robotic device from entering, or becomingproximate with, one or more objects and/or areas of operation. However,this solution is neither efficient nor practical since substantial extraequipment (e.g., barriers and/or other objects) may encumber routinemovement through the area of operation by the robotic device. Further,such an approach may involve an undesirable degree of humanintervention, which may decrease a level of autonomy of the system as awhole.

Various systems have been proposed to confine and control roboticdevices within subsections of workspaces. It can be advantageous toconfine a robotic vacuum, for example, in a portion of a workspace sothat it can adequately clean that space before moving on to anotherarea. As such, systems and methods for establishing virtual boundariesfor robotic devices are provided herein.

SUMMARY

Some embodiments include a method for detecting an alignment of a robotwith a virtual line, including: transmitting, with at least one firsttransmitter, a first signal; receiving, with a first receiver and asecond receiver, the first signal, wherein the first receiver and thesecond receiver are housed within a first passage and a second passage,respectively; detecting, with a controller coupled to the first receiverand the second receiver, the robot is aligned with the virtual line whenthe first receiver and the second receiver simultaneously receive thefirst signal, the virtual line being in line with and located at amidpoint between the first passage and the second passage; andexecuting, with the robot, a particular movement type when the robot isaligned with the virtual line.

Some embodiments provide a system, including: at least one firsttransmitter; a first receiver and a second receiver housed within afirst passage and a second passage, respectively; a controller coupledto the first receiver and the second receiver; and a robot; wherein thesystem is configured to: transmit, with the at least one first receiver,a first signal; receive, with the first receiver and the secondreceiver, the first signal; detect, with the controller, the robot isaligned with a virtual line when the first receiver and the secondreceiver simultaneously receive the first signal, the virtual line beingin line with and located at a midpoint between the first passage and thesecond passage; and instruct the robot to execute a particular movementtype when the robot is aligned with the virtual line.

BRIEF DESCRIPTION OF DRAWINGS

Non-limiting and non-exhaustive features of the present invention aredescribed with reference to the following figures, wherein likereference numerals refer to like parts throughout the various figures.

FIG. 1 illustrates an example of the operation of a virtual boundarysystem embodying features of the present invention;

FIG. 2 illustrates a robotic device embodying features of the presentinvention;

FIG. 3 illustrates a virtual boundary device embodying features of thepresent invention;

FIG. 4 illustrates the operation of a robotic device approaching avirtual boundary embodying features of the present invention;

FIG. 5 illustrates the operation of a robotic device intersecting avirtual boundary embodying features of the present invention;

FIG. 6 illustrates an embodiment of a virtual boundary device embodyingfeatures of the present invention;

FIG. 7 illustrates an embodiment of a virtual boundary device embodyingfeatures of the present invention;

FIG. 8 illustrates a virtual boundary device embodying features of thepresent invention;

FIG. 9 illustrates virtual boundary devices embodying features of thepresent invention;

FIG. 10 illustrates a virtual boundary device embodying features of thepresent invention; and

FIG. 11 illustrates a virtual boundary device embodying features of thepresent invention.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The present invention will now be described in detail with reference toa few embodiments thereof as illustrated in the accompanying drawings.In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill be apparent, however, to one skilled in the art, that the presentinvention may be practiced without some or all of these specificdetails. In other instances, well known process steps and/or structureshave not been described in detail in order to not unnecessarily obscurethe present invention.

Various embodiments are described hereinbelow, including methods andtechniques. It should be kept in mind that the invention might alsocover articles of manufacture that includes a computer readable mediumon which computer-readable instructions for carrying out embodiments ofthe inventive technique are stored. The computer readable medium mayinclude, for example, semiconductor, magnetic, opto-magnetic, optical,or other forms of computer readable medium for storing computer readablecode. Further, the invention may also cover apparatuses for practicingembodiments of the invention. Such apparatus may include circuits,dedicated and/or programmable, to carry out tasks pertaining toembodiments of the invention. Examples of such apparatus include ageneral-purpose computer and/or a dedicated computing device whenappropriately programmed and may include a combination of acomputer/computing device and dedicated/programmable circuits adaptedfor the various tasks pertaining to embodiments of the invention. Thedisclosure described herein is directed generally to one or moreprocessor-automated methods and/or systems that generate one or morevirtual barriers for restricting or permitting autonomous robotic devicemovement within or out of a working area.

As understood herein, the term “robot” or “robotic device” may bedefined generally to include one or more autonomous devices havingcommunication, mobility, and/or processing elements. For example, arobot or robotic device may comprise a casing or shell, a chassisincluding a set of wheels, a motor to drive wheels, a receiver thatacquires signals transmitted from, for example, a transmitting beacon, aprocessor, and/or controller that processes and/or controls motor andother robotic autonomous or cleaning operations, network or wirelesscommunications, power management, etc., and one or more clock orsynchronizing devices.

Preferably one or more virtual boundary devices having one or morereceivers, transmitters, or transceivers are provided to be portable andself-powered. In embodiments, a user may easily position a virtualboundary device in order to create a virtual boundary for the roboticdevice. The robotic device detects the position of the virtual boundarywhen it approaches it through communication between the robotic deviceand the virtual boundary device. Once the robotic device has detectedits close proximity to the boundary it will alter its movement to avoidcrossing the boundary.

FIG. 1 illustrates an example of the operation of virtual boundarysystem 100 embodying features of the present invention. Virtual boundarydevice 102 may be placed in a position where the user desires torestrict the movement of robotic device 104. Virtual boundary device 102may have one or more paired receivers that establish virtual boundaries.As illustrated, two sets of paired receivers 106 and 108 are configuredfor providing virtual boundaries. As may be seen, receiver pair 106establishes virtual boundary 110 and receiver pair 108 establishes avirtual boundary 112. Receiver pairs 106 and 108 may be either activedevices which send and receive signals or passive devices which onlyreceive signals in order to establish virtual boundaries. Asillustrated, receiver pairs 106 and 108 may be pivotally coupled withvirtual boundary device 102 such that a user may adjust the respectivepositions and angles of virtual boundaries 110 and 112 about pivot point130.

As illustrated, robotic device 104 may, in the course of executing acoverage pattern for a work area, move in direction 140 toward virtualboundary 110. When robotic device 104 is positioned approximately alongvirtual boundary 110, receiver pair 106 may substantially simultaneouslyreceive a signal emitted by robotic device 104 and virtual boundarydevice 102 may send a signal to robotic device 104 to take anappropriate action to avoid crossing boundary 110. In embodiments, therobotic device may alter its movement in any number of ways such as,stopping, slowing, and changing course without limitation. Inembodiments, other appropriate actions may include triggering analgorithm or marking the present location as a boundary on a map withoutlimitation. In further embodiments methods may allow robotic devices topass a virtual boundary after a number of times of encountering thevirtual boundary. In so doing, a work area may be completed before arobotic device moves across the virtual boundary to another work area.In other embodiments, methods may provide location information as arobotic device crosses a virtual boundary. For example, when a boundarysystem is placed at an entrance threshold, a robotic device crossing thevirtual boundary provided may signal that the robotic device has entereda particular room and is now covering that room.

In some embodiments, receiver pairs 106 and 108 are passive deviceswhich receive signals in order to establish a boundary. Receiver pairs106 and 108 may each be comprised of two focused receivers that are ableto receive a signal from robotic devices along substantially a singlevirtual boundary or plane which separates a desired robot work area froman area where the robotic device is prohibited. In an embodiment,receiver pairs 106 and 108 are each comprised of a pair of receiverspositioned such that a signal may only be received at both receiverssubstantially simultaneously when the origin of the signal issubstantially along the virtual boundary or plane.

The general method of operation of embodiments may now be disclosed. Inembodiments, robotic devices may provide a continuous, semi-continuous,or pulsed robotic device signal as the robotic device moves about in itsassigned work area. Each receiver pair may be monitored for detection ofa robotic device signal. When both receivers of a receiver pairsubstantially simultaneously detect a robotic device signal, the roboticdevice emitting the robotic device signal will be positioned along avirtual boundary established by the receiver pair. A virtual boundarydevice will then send a boundary signal received by the robotic device.When the robotic device receives the boundary signal its movement isaltered to avoid crossing the virtual boundary. In embodiments, therobotic device may alter its movement in any number of ways such as,stopping, slowing, and changing course without limitation. Inembodiments, other appropriate actions may include triggering analgorithm or marking the present location as a boundary on a map withoutlimitation. In further embodiments methods may allow robotic devices topass a virtual boundary after a number of times of encountering thevirtual boundary. In so doing, a work area may be completed before arobotic device moves across the virtual boundary to another work area.In other embodiments, methods may provide location information as arobotic device crosses a virtual boundary. For example, when a boundarysystem is placed at an entrance threshold, a robotic device crossing thevirtual boundary provided may signal that the robotic device has entereda particular room and is now covering that room. In some embodiments,receiver pairs may be configured to receive robotic device signalsconstantly. In other embodiments receiver pairs may be configured toreceive robotic device signals only on a desired schedule. In addition,in some embodiments, the robotic device signal may be configured totransmit only on a desired schedule. Furthermore, in embodiments, theboundary signal may be configured to transmit only on a desiredschedule. In this manner, a robotic device may avoid a virtual boundaryat designated times (such as during work hours) and ignore a virtualboundary at other times (such as during off hours).

FIG. 2 illustrates robotic device 104 embodying features of the presentinvention and/or having the type and functionality of a samplerepresentative robotic device. As illustrated, robotic device 104 mayinclude without limitation casing or shell 202, chassis 220, wheels 218,motor 214 for driving wheels 218, receiver 216 that detects transmittedsignals, processor 224 and/or controller 226 to process and/or controlmotor and other robotic autonomous operations, network or wirelesscommunications, power management, etc., and one or more clock orsynchronizing devices 230. Device 104 may additionally include localdigital memory or accessible storage unit 240 and wireless sonar/radiosensor and/or telecommunications transceiver 250 for mobilecommunication interface with a network or other wireless communicationdevice, or boundary transceivers.

FIG. 3 illustrates virtual boundary device 300 embodying features of thepresent invention. As illustrated, virtual boundary device 300 mayinclude housing 302. Within housing 302, receiver pair 310 and 312 areeach located at the terminal end of each of passages 306 and 308respectively. The combination of passages and receiver pair may betermed a virtual boundary component. Passages 306 and 308 extend fromsurface 304 to receiver pair 310 and 312 at an angle. The angle utilizedprevents receiver pair 310 and 312 from substantially simultaneouslyreceiving a signal unless the signal is emitted from a robotic devicepositioned along a line as illustrated by line 314. Thus, when a roboticdevice emitting a robotic device signal is positioned along virtualboundary 314, receiver pair 310 and 312 may substantially simultaneouslyreceive a signal and thereby the robotic device may be caused to avoidthe virtual boundary. In embodiments, the robotic device may avoid thevirtual boundary by altering its movement in any number of ways such as,stopping, slowing, and changing course without limitation. Inembodiments, other appropriate actions may include triggering analgorithm or marking the present location as a boundary on a map withoutlimitation. In further embodiments methods may allow robotic devices topass a virtual boundary after a number of times of encountering thevirtual boundary. In so doing, a work area may be completed before arobotic device moves across the virtual boundary to another work area.In other embodiments, methods may provide location information as arobotic device crosses a virtual boundary. For example, when a boundarysystem is placed at an entrance threshold, a robotic device crossing thevirtual boundary provided may signal that the robotic device has entereda particular room and is now covering that room. In embodiments,receiver pairs may be configured for receiving various signals such as,for example: infrared, laser, radio frequency, Wi-Fi, sonar, light,sound waves, global positioning signal, cellular communication devicetransmissions, magnetic field signal, or any other suitable wirelesssignal sent by a robotic device. In embodiments, the passages 306 areset at an angle with respect to a virtual boundary line. Passage anglesmay be in a range of approximately −90 to 90 degrees with respect to avirtual boundary line and preferably approximately −45 to 45 degreeswith respect to a virtual boundary line. In addition, in embodiments,passage angles between sensors may be the same, may be inverselyrelated, or may be different from each other without limitation.

In like manner, within housing 302, receiver pair 330 and 332 are eachlocated at the terminal end of each of passages 326 and 328respectively. Passages 326 and 328 extend from surface 324 to receiverpair 330 and 332 at an angle. The angle utilized prevents receiver pair330 and 332 from substantially simultaneously receiving a signal unlessthe signal is emitted from a robotic device positioned along a line asillustrated by line 334. Thus, when a robotic device emitting a roboticdevice signal is positioned along virtual boundary 334, receiver pair330 and 332 may substantially simultaneously receive a signal andthereby the robotic device may be caused to avoid the virtual boundary.In embodiments, receiver pairs may be configured for receiving varioussignals such as, for example: infrared, laser, radio frequency, Wi-Fi,sonar, light, sound waves, global positioning signal, cellularcommunication device transmissions, magnetic field signal, or any othersuitable wireless signal sent by a robotic device. In embodiment, thepassages 326 are set at an angle with respect to a boundary line 334.

Referring briefly to both FIGS. 2 and 3 , in embodiments, passages 306and 308 as well as receiver pair 310 and 312 may be positioned atsubstantially the same height as a transceiver 250 of robotic device 104for improved reception of the signal from the robotic device. Likewise,in embodiments, passages 326 and 328 as well as receiver pair 330 and332 may be positioned at substantially the same height as a transceiver250 of robotic device 104 for improved reception of the signal from therobotic device.

Returning to FIG. 3 , virtual boundary device 300 may include acontroller 340 which may be electrically coupled with each of receiver310, 312, 330, and 332. Further, transmitter 350 may be electricallycoupled with controller 340. Transmitter 350 may be a transmitter forinfrared, laser, radio frequency, Wi-Fi, sonar light, sound waves,global positioning signal, cellular communication device transmissions,magnetic field signal, or other suitable wireless transmitter which iscompatible with a signal which may be received by the robotic device.Controller 340 may function to detect whether both receivers of anyreceiver pair substantially simultaneously receives an incoming signal.Any time a receiver pair substantially simultaneously receives anincoming signal, controller 340 enables transmitter 350 to transmitboundary signals, which may be received by a robotic device positionedalong a virtual boundary and which may be programmed to alter itsmovement path upon receipt of the boundary signal. The controller 340may be implemented with AND gate logic circuits. Other implementationsmay also be used, such as processor based controllers.

In embodiments, housings may be constructed of a type of material and athickness which effectively blocks the robotic device signal.Alternatively, the circuit 340 may monitor the signal strength of therobotic device signal at each receiver and only enables the transmitterwhen the signal strength from both receivers exceeds a threshold amountwhich indicates that the robotic device signal is passing through bothpassages to the respective receivers.

FIG. 4 illustrates the operation of robotic device 104 approachingvirtual boundary 314 embodying features of the present invention. Themethod will now be described. Virtual boundary device 300 may bepositioned to establish virtual boundaries or planes 314 and 334.Virtual boundaries 314 and 334 apportion an area into a robotic devicework area 410 and out of bounds area 412. In operation, robotic device104 may be enabled to cover a surface area in a defined or randompattern. As such, robotic device 104 may move within the work area 410co-located with virtual boundary 314. During movement, robotic device104 may be configured to emit a continuous, semi-continuous, or pulsedrobotic device signal 420 from its transceiver 250 (see FIG. 2 ). Inembodiments, robotic device signals may include infrared, laser, radiofrequency, Wi-Fi, sonar, light, sound waves, global positioning signal,cellular communication device transmissions, magnetic field signal, orother suitable wireless signal type.

Further, during movement robotic device 104 may travel along direction430 toward virtual boundary 314. As shown in FIG. 4 , the robotic device104 is still located a distance from virtual boundary 314. At theposition illustrated, robotic device signal 420 is only being receivedby one receiver of a receiver pair associated with boundary 314. Assuch, a controller in virtual boundary device 300 detects that only oneof receiver pair is receiving robotic device signal 420 and does notenable transmission of a boundary signal.

FIG. 5 illustrates the operation of robotic device 104 intersectingvirtual boundary 314 embodying features of the present invention. Oncerobotic device 104 is located at virtual boundary 314, robotic devicesignal 420 is substantially simultaneously received by a receiver pairof virtual boundary device 300. A controller detects a receiver pair isreceiving robotic device signal 420. The controller then enables atransmitter to send an outbound signal to robotic device 104. Roboticdevice 104 receives the boundary signal and its controller instructs therobotic device 104 to alter its movement to avoid crossing virtualboundary 314. As an illustrated example, robotic device 104 may reverseits path and proceed in direction 510. As robotic device 104 moves awayfrom virtual boundary 314, both receivers of a receiver pair are nolonger substantially simultaneously receiving robotic device signal 420.The virtual boundary device controller detects the lack of a signal atthe receiver pair and the virtual boundary device controller thenterminates the boundary signal. Thus, the robotic device is preventedfrom crossing the virtual boundary 314 and equally prevented fromcovering out of bounds area 412.

FIG. 6 illustrates an embodiment of virtual boundary device embodyingfeatures of the present invention. As illustrated, virtual boundarydevice 600 is rotatably adjustable. Further illustrated, upper portion602 is rotatably coupled with lower portion 604. Upper portion 602 has apair of passages 610 and each passage terminates at a receiver (notshown). The receivers of passages 610 are a receiver pair. Passages 610and corresponding receiver pair are configured similar to theembodiments described above such that they define a virtual boundary612. Lower portion 604 also has passages 620 and each passage 620terminates at a receiver (not shown). Passages 620 and correspondingreceiver pair are configured to define virtual boundary 622. Virtualboundary device 600 may also include a controller and transmittersimilar to those previously described above.

In operation, a user may rotate upper portion 602 in direction 630 or640 relative to bottom portion 604. In this manner, virtual boundary 612may be adjusted relative to virtual boundary 622. This configurationallows users to customize the angle between virtual boundaries to fitthe particular needs of a working environment. In some embodiments,virtual boundaries may be activated and deactivated through a switch orbutton 650 that activates and deactivates the corresponding receiverpairs. Switch 650 may control a switch located between the power sourceand the receiver set.

FIG. 7 illustrates an embodiment of virtual boundary device 700embodying features of the present invention. As illustrated, virtualboundary device 700 includes cylindrically shaped housing 702. Housing702 includes top surface 704 and side surface 706. Side surface 706includes a number of virtual boundary components 710 positioned alongthe circumference of housing 702. Each virtual boundary componentincludes a pair of passages and receivers similar to those describedabove. A plurality of buttons 720 may be positioned along top surface704. Each button may be associated with one of the virtual boundarycomponents 710. The button may control a switch located between a powersource and the receivers located within the respective virtual boundarycomponent 710. A user may selectively enable different virtual boundarycomponents to configure the appropriate virtual boundaries for therobotic device. FIG. 7 illustrates an example where two of the virtualboundary components are enabled, thereby defining two virtual boundaries730 and 740. Other configurations are possible by enabling or disablingselected setters 720 as desired.

The number and positioning of sets of receivers may vary and is notlimited. The designs shown are for illustration purposes only and arenot meant to be restrictive. Various types of wireless signals, such asinfrared light, laser, radio frequencies, Wi-Fi signals, sonar signals,light, sound waves, global positioning signal, cellular communicationdevice transmissions, magnetic field signal, or any other availablewireless signal may be used for sending signals from the robotic deviceto the transceiver and for sending signals from the transceiver'semitter to the robotic device.

FIG. 8 illustrates a virtual boundary device embodying features of thepresent invention. As illustrated, virtual boundary device 800 mayinclude housing 802. Within housing 802, receiver pair 810 and 812 areeach located at the terminal end of each of passages 806 and 808respectively. The combination of passages and receiver pair may betermed a virtual boundary component. Passages 806 and 808 extend fromsurface 804 to receiver pair 810 and 812 at an angle. The angle utilizedprevents receiver pair 810 and 812 from substantially simultaneouslyreceiving a signal unless the signal is emitted from a robotic devicepositioned along a line as illustrated by line 814. Thus, when a roboticdevice emitting a robotic device signal is positioned along virtualboundary 814, receiver pair 810 and 812 may substantially simultaneouslyreceive a signal and thereby the robotic device may be caused to avoidthe virtual boundary.

Further illustrated are a number of baffles 824 positioned along thewalls of passage 806. Baffles may be utilized to further narrow thereception range of receiver pair 810 and 812 and reduce reception ofreflected signals being transmitted toward receiver pair 810 and 812.Baffles may be angled toward opening of passages. In embodiments,baffles may be manufactured from signal absorbing materials or signalreflective materials without limitation. In further embodiments, bafflesmay be angled at a range of approximately 10 to 60 degrees, morepreferably 40 degrees. As may be appreciated, different angles mayimpart different signal reception characteristics.

In embodiments, the robotic device may avoid the virtual boundary byaltering its movement in any number of ways such as, stopping, slowing,and changing course without limitation. In embodiments, otherappropriate actions may include triggering an algorithm or marking thepresent location as a boundary on a map without limitation. In furtherembodiments methods may allow robotic devices to pass a virtual boundaryafter a number of times of encountering the virtual boundary. In sodoing, a work area may be completed before a robotic device moves acrossthe virtual boundary to another work area. In other embodiments, methodsmay provide location information as a robotic device crosses a virtualboundary. For example, when a boundary system is placed at an entrancethreshold, a robotic device crossing the virtual boundary provided maysignal that the robotic device has entered a particular room and is nowcovering that room. In embodiments, receiver pairs may be configured forreceiving various signals such as, for example: infrared, laser, radiofrequency, Wi-Fi, sonar, light, sound waves, global positioning signal,cellular communication device transmissions, magnetic field signal, orany other suitable wireless signal sent by a robotic device. Inembodiment, the passages 806 are set at an angle with respect to avirtual boundary line. Passage angles may be in a range of approximately−90 to 90 degrees with respect to a virtual boundary line, andpreferably approximately −45 to 45 degrees with respect to a virtualboundary line. In addition, in embodiments, passage angles betweensensors may be the same, may be inversely related, or may be differentfrom each other without limitation.

Further illustrated is passage 820 and receiver 822. As illustrated,passage 820 may be positioned between passage 806 and passage 808.Unlike passages 806 and 808, passage 820 is not angled. Rather passage820, in embodiments, may be substantially parallel with respect tovirtual boundary 814. In embodiments, an additional receiver may provideaddition control inputs. For example, in an embodiment, when a signal isreceived at receivers 810 and 822, an instruction may be transmitted toa robotic device as, for example, “slow” or “begin turn.” Likewise, whena signal is received at receivers 810 and 822 a further instruction maybe transmitted to a robotic device. In this manner, a robotic device maybe more finely tuned to operate within a virtual boundary.

Returning to FIG. 8 , virtual boundary device 800 may include acontroller 840 which may be electrically coupled with each of receiver810, 812, and 822. Further, transmitter 850 may be electrically coupledwith controller 840. Transmitter 850 may be a transmitter for infrared,laser, radio frequency, Wi-Fi, sonar, light, sound waves, globalpositioning signal, cellular communication device transmissions,magnetic field signal, or other suitable wireless transmitter which iscompatible with a signal which may be received by the robotic device.Controller 840 may function to detect whether both receivers of anyreceiver pair substantially simultaneously receives an incoming signal.Any time a receiver pair substantially simultaneously receives anincoming signal, controller 840 enables transmitter 850 to transmitboundary signals, which may be received by a robotic device positionedalong a virtual boundary and which may be programmed to alter itsmovement path upon receipt of the boundary signal. The controller 840may be implemented with AND gate logic circuits. Other implementationsmay also be used, such as processor based controllers.

In embodiments, housings may be constructed of a type of material and athickness which effectively blocks the robotic device signal.Alternatively, the circuit 840 may monitor the signal strength of therobotic device signal at each receiver and only enables the transmitterwhen the signal strength from both receivers exceeds a threshold amountwhich indicates that the robotic device signal is passing through bothpassages to the respective receivers.

It may be appreciated that robotic device embodiments disclosed hereinmay be autonomous, semi-autonomous, or remote controlled. That is,robotic device embodiments are not limited in response to virtualboundary systems provided herein. For example, a robotic device may,upon reaching a steep turn, engage a semi-autonomous vehicle on a trackto navigate the steep turn. It may be further appreciated that manytypes of coordination with systems provided herein may be contemplated.

FIG. 9 illustrates virtual boundary devices embodying features of thepresent invention. As noted above, in embodiments passages may be atvarious angles with respect to a virtual boundary line. In embodiments,passage angles may be in a range of approximately −90 to 90 degrees withrespect to a virtual boundary line and preferably approximately −45 to45 degrees with respect to a virtual boundary line. In addition, inembodiments, passage angles between sensors may be the same, may beinversely related, or may be different from each other withoutlimitation. Various passage configurations are illustrated in FIG. 9 .For example, virtual boundary device 900 may include a pair of passages902A and 902B, which passages may be inwardly facing with respect tovirtual boundary line 910. Lines 904A and 904B are parallel with virtualboundary line 910 and are provided for reference. As illustrated,passage 902A is angled at θ¹ 908A and may received signals along line906A. Likewise, passage 902B is angled at θ² 908B and may receivedsignals along line 906B. In another embodiment, virtual boundary device920 may include a pair of passages 922A and 922B, which passages may beoutwardly facing with respect to virtual boundary line 930. Lines 924Aand 924B are parallel with virtual boundary line 930 and are providedfor reference. As illustrated, passage 922A is angled at θ¹ 928A and mayreceived signals along line 926A. Likewise, passage 922B is angled at θ²928B and may received signals along line 926B. In a further embodiment,virtual boundary device 940 may include a pair of passages 942A and942B, which passages may be rightward facing with respect to virtualboundary line 950. Lines 944A and 944B are parallel with virtualboundary line 950 and are provided for reference. As illustrated,passage 942A is angled at θ¹ 948A and may received signals along line946A. Likewise, passage 942B is angled at θ² 948B and may receivedsignals along line 946B. It may be seen from the foregoing examples thatpassages may be configured at any angle without departing fromembodiments provided herein. In addition, angles between passages may bethe same or different without limitation in embodiments.

FIG. 10 illustrates a virtual boundary device embodying features of thepresent invention. As illustrated, virtual boundary device 1000 mayinclude a pair of passages 1002A and 1002B, which passages may beforward facing with respect to virtual boundary line 1010. Asillustrated, passage 1002A has an angle θ¹ 1008A of approximately zerowith respect to virtual boundary line 1010. That is, passage 1002A issubstantially parallel with virtual boundary line 1010. Further, passage1002A may receive signals along line 1006A. Further illustrated, passage1002B has an angle θ² 1008B of approximately zero with respect tovirtual boundary line 1010. That is, passage 1002B is substantiallyparallel with virtual boundary line 1010. Further, passage 1002B mayreceive signals along line 1006B. It may be seen from the foregoingexamples that passages may be configured at any angle without departingfrom embodiments provided herein. In addition, angles between passagesmay be the same or different without limitation in embodiments.

Alternate Embodiments

FIG. 11 illustrates a virtual boundary device embodying features of thepresent invention. In particular, FIG. 11 is an illustrativerepresentation of a passage embodiment using additional opticalconfigurations. As illustrated, virtual boundary device 1100 may includepassage 1102 that, unlike previous embodiments, terminates in reflectiveelement 1106. As illustrated, passage 1012 is substantially parallelwith virtual boundary line 1110. In embodiments, reflective element 1106may be utilized to reflect received signals 1104 toward sensor 1112.Reflective element embodiments may be matched to reflect a particularsignal or range of signals as desired. In addition, virtual boundarydevice 1100 may further include focusing element 1108 for focusingsignal 1104 toward sensor 1112. Any type of suitable focusing elementknown in the art may be utilized without departing from embodimentscontemplated herein. As above passages utilizing optical configurationsmay be at various angles with respect to a virtual boundary line withoutlimitation and without departing from embodiments provided herein.

The foregoing descriptions of specific embodiments of the invention havebeen presented for purposes of illustration and description. They arenot intended to be exhaustive or to limit the invention to the preciseforms disclosed. Obviously, many modifications and variations arepossible in light of the above teaching. The embodiments were chosen anddescribed in order to explain the principles and the application of theinvention, thereby enabling others skilled in the art to utilize theinvention in its various embodiments and modifications according to theparticular purpose contemplated. The scope of the invention is intendedto be defined by the claims appended hereto and their equivalents.Further, the Abstract is provided herein for convenience and should notbe employed to construe or limit the overall invention, which isexpressed in the claims. It is therefore intended that the followingappended claims be interpreted as including all such alterations,permutations, and equivalents as fall within the true spirit and scopeof the present invention.

The invention claimed is:
 1. A method for detecting an alignment of arobot with a virtual line, comprising: transmitting, with at least onefirst transmitter, a first signal; receiving, with a first receiver anda second receiver, the first signal, wherein the first receiver and thesecond receiver are housed within a first passage and a second passage,respectively; detecting, with a controller coupled to the first receiverand the second receiver, the robot is aligned with the virtual line whenthe first receiver and the second receiver simultaneously receive thefirst signal, the virtual line being in line with and located at amidpoint between the first passage and the second passage; andexecuting, with the robot, a particular movement type when the robot isaligned with the virtual line.
 2. The method of claim 1, detecting therobot is aligned with the virtual line further comprises: transmitting,with at least one second transmitter, a second signal indicating thatthe robot is aligned with the virtual line upon detecting the robot isaligned with the virtual line; and receiving, with at least one thirdreceiver, the second signal, wherein the second signal triggers therobot to execute the particular movement type.
 3. The method of claim 1,further comprising: determining, with a processor of the robot, alocation of the robot based on communications between the at least onefirst transmitter and at least one of the first receiver and the secondreceiver.
 4. The method of claim 1, wherein the particular movement typecomprises at least one of reversing, moving forward, and turning.
 5. Themethod of claim 1, wherein the robot slows down when the robot isaligned with the virtual line.
 6. The method of claim 1, wherein thefirst receiver and the second receiver are configured to only receivethe first signal during a designated time.
 7. The method of claim 1,wherein the first signal is only transmitted during a designated time.8. The method of claim 1, wherein the first passage and the secondpassage include a plurality of baffles positioned along their respectivepassage walls.
 9. The method of claim 8, wherein the plurality ofbaffles of the first passage and the second passage are angled towardsan opening of the respective passage.
 10. The method of claim 1, whereinthe first passage and the second passage are oriented in such a way tophysically prevent the first receiver and the second receiver fromreceiving the first signal simultaneously except when the robot isaligned with the virtual line.
 11. A system, comprising: at least onefirst transmitter; a first receiver and a second receiver housed withina first passage and a second passage, respectively; a controller coupledto the first receiver and the second receiver; and a robot; wherein thesystem is configured to: transmit, with the at least one first receiver,a first signal; receive, with the first receiver and the secondreceiver, the first signal; detect, with the controller, the robot isaligned with a virtual line when the first receiver and the secondreceiver simultaneously receive the first signal, the virtual line beingin line with and located at a midpoint between the first passage and thesecond passage; and instruct the robot to execute a particular movementtype when the robot is aligned with the virtual line.
 12. The system ofclaim 11, further comprising: at least one second transmitter; and athird receiver; and wherein the system is further configured to:transmit, with the at least one second transmitter, a second signalindicating that the robot is aligned with the virtual line; and receive,with the third receiver, the second signal, wherein the second signaltriggers the robot to execute the particular movement type.
 13. Thesystem of claim 11, wherein the system is further configured to:determine a location of the robot based on communications between the atleast one first transmitter and at least one of the first receiver andthe second receiver.
 14. The system of claim 11, wherein the particularmovement type comprises at least one of reversing, moving forward, andturning.
 15. The system of claim 11, wherein the robot slows down whenthe robot is aligned with the virtual line.
 16. The system of claim 11,wherein the first receiver and the second receiver are configured toonly receive the first signal during a designated time.
 17. The systemof claim 11, wherein the first signal is only transmitted during adesignated time.
 18. The system of claim 11, wherein the first passageand the second passage include a plurality of baffles positioned alongtheir respective passage walls.
 19. The system of claim 18, wherein theplurality of baffles of the first passage and the second passage areangled towards an opening of the respective passage.
 20. The system ofclaim 11, wherein the first passage and the second passage are orientedin such a way to physically prevent the first receiver and the secondreceiver from receiving the first signal simultaneously except when therobot is aligned with the virtual line.